Prematurity and Delayed Diagnosis of Down Syndrome

OBJECTIVE The aim of this study was to compare age at diagnosis of common aneuploidies by gestational age at birth to determine if prematurity is associated with delayed diagnosis. METHODS We conducted a retrospective cohort study of neonates with Patau syndrome (PS), Edwards syndrome (ES) or Down syndrome (DS) admitted to any Nationwide Children’s Hospital (NCH) neonatal intensive care unit (NICU) from 2010-2021. The exposure of interest was birth gestational age (GA): < 34 weeks, 34-36 weeks and ≥ 37 weeks. Age at diagnosis for PS/ES and DS was compared between gestational age groups using the Jonckheere-Terpstra rank-based nonparametric test for ordered alternatives. RESULTS Among neonates with PS/ES, the median age [days (interquartile range)] at karyotypic diagnosis for preterm, late preterm, and term/post-term neonates was 3 (2-7), 4 (3-9), and 3 (3-5) days, respectively (trend not significant). Among neonates with DS, the median age (days) at karyotypic diagnosis for preterm, late preterm, and term/post-term neonates was 6 (5-10), 5 (3-7), and 4 (3-5), respectively. The trend of increasing age at diagnosis with increasing prematurity was significant (p<.01). CONCLUSIONS Increasing prematurity was associated with increasing age at diagnosis of DS but not PS/ES in a large network of Level III/IV NICUs.